Bring r5483 "Fix direct loading of global function prototypes" to 2.2.

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
===================================================================
--- src/arm/stub-cache-arm.cc	(revision 5484)
+++ src/arm/stub-cache-arm.cc	(working copy)
@@ -266,7 +266,12 @@
 
 
 void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(
-    MacroAssembler* masm, int index, Register prototype) {
+    MacroAssembler* masm, int index, Register prototype, Label* miss) {
+  // Check we're still in the same context.
+  __ ldr(prototype, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ Move(ip, Top::global());
+  __ cmp(prototype, ip);
+  __ b(ne, miss);
   // Get the global function with the given index.
   JSFunction* function = JSFunction::cast(Top::global_context()->get(index));
   // Load its initial map. The global functions all have initial maps.
@@ -1494,7 +1499,7 @@
         __ b(hs, &miss);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::STRING_FUNCTION_INDEX, r0);
+            masm(), Context::STRING_FUNCTION_INDEX, r0, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), r0, holder, r3,
                         r1, r4, name, &miss);
       }
@@ -1514,7 +1519,7 @@
         __ bind(&fast);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::NUMBER_FUNCTION_INDEX, r0);
+            masm(), Context::NUMBER_FUNCTION_INDEX, r0, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), r0, holder, r3,
                         r1, r4, name, &miss);
       }
@@ -1537,7 +1542,7 @@
         __ bind(&fast);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::BOOLEAN_FUNCTION_INDEX, r0);
+            masm(), Context::BOOLEAN_FUNCTION_INDEX, r0, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), r0, holder, r3,
                         r1, r4, name, &miss);
       }